Have Slide Rule, Will Keep Lip Zipped

Around Washington, secretive types who identify themselves simply as Defense Department employees are often greeted by clerks and waitresses with Oh! You must work for the NSA! The National Security Agency, the puzzle palace of U.S. intelligence eavesdroppers, has always preferred to stay in the shadows. But lately the nsa has been forced to edge into the light. NSA recruiters showed up at a mathematics conference in Baltimore last month openly seeking specialists in areas like numbers theory for code-breaking jobs. Only U.S. citizens need apply.